This invention relates to the use of laser light to ablate materials.
Recently, nanoparticles have been the focus of much research. Certain governmental agencies around the globe have indicated efficient methods of nanoparticle production is desired, and funding toward such research has ensued. Nanoparticles of a variety of materials are interesting because such particles sometimes exhibit different physical properties as compared to larger sized particles of the same material. Ferrous oxide (rust), for instance, is white and translucent and magnetic when of nanoparticle size.
In addition, it has been suggested that ceramic materials, such as Si.sub.3 N.sub.4 and SiC, of higher quality may be produced when the starting materials are of small size, free of agglomeration, in a narrow range of sizes, of spherical shape and of high purity. Most powders do not possess these characteristics. Methods of making such starting materials in large volume is highly desirable.
Previously, the production of nanoparticles has been by methods such as vacuum synthesis, gas-phase synthesis, condensed phase synthesis, high speed deposition by ionized cluster beams, consolidation, high speed milling, mixalloy processing, deposition methods and sol-gel method. These methods suffer from a variety of defects including agglomeration, broad size distribution, or low volume production.
Additionally, nanoparticles have been produced by ablation of bulk, planar surfaces using laser light. This method does produce nanoparticles, but energy requirements are undesirably high and yield of nanoparticles is undesirably low. Moreover, the size distribution of nanoparticles using this method is broad.
It can be seen new methods of nanoparticle production would be highly desirable. It can further be seen that it would be desirable if such new methods produced nanoparticles in good yield, at higher efficiencies, and to provide a more narrow size distribution of nanoparticles.